Extended Data Fig. 2: daLUXendin544 and daLUXendin660 specifically label endogenous GLP1R and GIPR.
From: Fluorescent GLP1R/GIPR dual agonist probes reveal cell targets in the pancreas and brain
a) daLUXendin660 and LUXendin551 (LUX551; GLP1R probe) labelling co-localize in MIN6-CB4 beta cells, which endogenously express GLP1R (n = 16 images from 4 wells, 2 independent repeats). b) daLUXendin660 and sGIP549 (GIPR probe) co-localize in MIN6-CB4 beta cells, which endogenously express GIPR (n = 16 images from 4 wells, 2 independent repeats). c) daLUXendin544 labelling co-localizes with BG-Sulfo646 SNAP label in GLP1RSNAP/SNAP mouse islets (n = 24 islets from 5 mice). d, e) daLUXendin544 labels membrane and cytoplasmic (that is, internalized) GLP1R pools in GLP1RSNAP/SNAP mouse islets, labelled using the cell impermeable SNAP label, BG-Sulfo646, and shown using full width at half maximum (FWHM) (line placement used for FHWM calculation is shown) (n = at least 18 islets from at least 5 mice). f) daLUXendin544 engages distinct GLP1R/GIPR pools in α cells versus β cells, with more membrane labelling in β cells (arrows show membrane labelling) (n = 37 islets from 3 mice). g) daLUXendin544 and sGIP648 (GIPR) labelling co-localize in mouse islets (n = 37 islets from 3 mice). h) Analysis showing strong co-localization between daLUXendin544 and either GLP1R or GIPR, labelled using LUXendin645 (LUX645) and sGIP648, respectively (n = 43 islets from 2 mice). i, j) daLUXendin544 labelling is reduced in GLP1RKO/KO islets, and further reduced in GLP1RKO/KO islets + 1 µM GIP Aib2 (n = 37 islets from 2 mice) (Kruskal-Walllis test with two-stage linear step-up procedure of Benjamini, Krieger and Yekutieli). Scale bar = 33.7 µm in a and b; scale bar = 53 µm in c, d, f, g and j. No changes are seen in vehicle-treated islets. Bar graphs show mean ± SEM. Exact p values are displayed on each graph.
